#include "putty.h"
#ifndef NO_GSSAPI
#include "pgssapi.h"
#include "sshgss.h"
#include "sshgssc.h"

/* Unix code to set up the GSSAPI library list. */

#if !defined NO_LIBDL && !defined NO_GSSAPI

const int ngsslibs = 4;
const char *const gsslibnames[4] = {
    "libgssapi (Heimdal)",
    "libgssapi_krb5 (MIT Kerberos)",
    "libgss (Sun)",
    "User-specified GSSAPI library",
};
const struct keyvalwhere gsslibkeywords[] = {
    {"libgssapi", 0, -1, -1},
    {"libgssapi_krb5", 1, -1, -1},
    {"libgss", 2, -1, -1},
    {"custom", 3, -1, -1},
};

/*
 * Run-time binding against a choice of GSSAPI implementations. We
 * try loading several libraries, and produce an entry in
 * ssh_gss_libraries[] for each one.
 */

static void gss_init(struct ssh_gss_library *lib,
                     void *dlhandle,
                     int id,
                     const char *msg)
{
  lib->id = id;
  lib->gsslogmsg = msg;
  lib->handle = dlhandle;

#define BIND_GSS_FN(name)                                                      \
  lib->u.gssapi.name = (t_gss_##name)dlsym(dlhandle, "gss_" #name)

  BIND_GSS_FN(delete_sec_context);
  BIND_GSS_FN(display_status);
  BIND_GSS_FN(get_mic);
  BIND_GSS_FN(import_name);
  BIND_GSS_FN(init_sec_context);
  BIND_GSS_FN(release_buffer);
  BIND_GSS_FN(release_cred);
  BIND_GSS_FN(release_name);

#undef BIND_GSS_FN

  ssh_gssapi_bind_fns(lib);
}

/* Dynamically load gssapi libs. */
struct ssh_gss_liblist *ssh_gss_setup(Conf *conf)
{
  void *gsslib;
  char *gsspath;
  struct ssh_gss_liblist *list = snew(struct ssh_gss_liblist);

  list->libraries = snewn(4, struct ssh_gss_library);
  list->nlibraries = 0;

  /* Heimdal's GSSAPI Library */
  if ((gsslib = dlopen("libgssapi.so.2", RTLD_LAZY)) != NULL)
    gss_init(&list->libraries[list->nlibraries++],
             gsslib,
             0,
             "Using GSSAPI from libgssapi.so.2");

  /* MIT Kerberos's GSSAPI Library */
  if ((gsslib = dlopen("libgssapi_krb5.so.2", RTLD_LAZY)) != NULL)
    gss_init(&list->libraries[list->nlibraries++],
             gsslib,
             1,
             "Using GSSAPI from libgssapi_krb5.so.2");

  /* Sun's GSSAPI Library */
  if ((gsslib = dlopen("libgss.so.1", RTLD_LAZY)) != NULL)
    gss_init(&list->libraries[list->nlibraries++],
             gsslib,
             2,
             "Using GSSAPI from libgss.so.1");

  /* User-specified GSSAPI library */
  gsspath = conf_get_filename(conf, CONF_ssh_gss_custom)->path;
  if (*gsspath && (gsslib = dlopen(gsspath, RTLD_LAZY)) != NULL)
    gss_init(&list->libraries[list->nlibraries++],
             gsslib,
             3,
             dupprintf("Using GSSAPI from user-specified"
                       " library '%s'",
                       gsspath));

  return list;
}

void ssh_gss_cleanup(struct ssh_gss_liblist *list)
{
  int i;

  /*
   * dlopen and dlclose are defined to employ reference counting
   * in the case where the same library is repeatedly dlopened, so
   * even in a multiple-sessions-per-process context it's safe to
   * naively dlclose everything here without worrying about
   * destroying it under the feet of another SSH instance still
   * using it.
   */
  for (i = 0; i < list->nlibraries; i++) {
    dlclose(list->libraries[i].handle);
    if (list->libraries[i].id == 3) {
      /* The 'custom' id involves a dynamically allocated message.
       * Note that we must cast away the 'const' to free it. */
      sfree((char *)list->libraries[i].gsslogmsg);
    }
  }
  sfree(list->libraries);
  sfree(list);
}

#elif !defined NO_GSSAPI

const int ngsslibs = 1;
const char *const gsslibnames[1] = {
    "static",
};
const struct keyvalwhere gsslibkeywords[] = {
    {"static", 0, -1, -1},
};

/*
 * Link-time binding against GSSAPI. Here we just construct a single
 * library structure containing pointers to the functions we linked
 * against.
 */

#include <gssapi/gssapi.h>

/* Dynamically load gssapi libs. */
struct ssh_gss_liblist *ssh_gss_setup(Conf *conf)
{
  struct ssh_gss_liblist *list = snew(struct ssh_gss_liblist);

  list->libraries = snew(struct ssh_gss_library);
  list->nlibraries = 1;

  list->libraries[0].gsslogmsg = "Using statically linked GSSAPI";

#define BIND_GSS_FN(name)                                                      \
  list->libraries[0].u.gssapi.name = (t_gss_##name)gss_##name

  BIND_GSS_FN(delete_sec_context);
  BIND_GSS_FN(display_status);
  BIND_GSS_FN(get_mic);
  BIND_GSS_FN(import_name);
  BIND_GSS_FN(init_sec_context);
  BIND_GSS_FN(release_buffer);
  BIND_GSS_FN(release_cred);
  BIND_GSS_FN(release_name);

#undef BIND_GSS_FN

  ssh_gssapi_bind_fns(&list->libraries[0]);

  return list;
}

void ssh_gss_cleanup(struct ssh_gss_liblist *list)
{
  sfree(list->libraries);
  sfree(list);
}

#endif /* NO_LIBDL */

#endif /* NO_GSSAPI */
